First it was that belated Chinese Lunar New Year's greeting.

Then came a similarly belated, yet in the White House's words, "lengthy" and "extremely cordial", telephone call.

To many who have waited in anxious anticipation for the completion of the diplomatic ritual, now is the time to heave that overdue sigh of relief. And for the Asia-Pacific region, it can now afford to breathe more freely.

Even after United States Defense Secretary Jim Mattis used his first official visit to Asia to allay fears over a possible military conflict in the South China Sea, there was lingering concern that the absence of the usual courtesy and formality from the new US leader might bode ill for the China-US relationship. After all, nobody knew for sure what US President Donald Trump had got up his sleeve thanks particularly to his previous harsh remarks on bilateral ties.

Should he seek to change the state of affairs by playing the Taiwan card and undermining the longstanding one-China policy, Sino-US relations will see earthshaking reversals. Which is why it would be unfair to blame people for nitpicking about the formalities. Indeed, the presence or absence of formalities may signify more than people believe.

But the phone conversation between the Chinese and US presidents Thursday night, Washington time went far beyond fulfilling the routine formalities and making up for the once missing symbolism. And that the White House described the phone conversation as "extremely cordial" and said the two presidents extended invitations to each other to visit their respective countries makes it more than the dispensing of a customary act.

Among the "numerous topics" they touched upon during the conversation over the phone, it was Taiwan that mattered the most.

If Mattis' reiteration of US commitment to diplomacy in the South China Sea alleviated fears over a possible China-US conflict there, Trump's latest pledge to honor the one-China policy removed a potentially more dangerous stumbling block for bilateral ties.

Now that the two most inflammable flashpoints in China-US ties have been taken care of, the precious predictability will do more than help allay concerns.

While it is true that either of the two issues could derail and upend the bilateral relationship, result in jitters and even head-on conflict, the constructive approach the Trump administration has finally demonstrated will create endless possibilities for this crucial relationship to grow and prosper, beneficial to the world at large.

This will become even more evident as representatives of both countries "engage in discussions and negotiations on various issues of mutual interest" - because their respective interests overlap more than their differences.

Since the Chinese Dream of national rejuvenation and the Trump presidency's aspiration to "make America great again" are essentially homogeneous, only cooperation can guarantee the peaceful environment their respective ambitions entail.

If Beijing and Washington can treat each other as "cooperative partners", as President Xi Jinping hopes, and "push bilateral relations to a historic new high", both countries will find themselves better off.

The fear-inspiring Thucydides trap is not inescapable if both Beijing and Washington believe they can win together.